Podcast
Questions and Answers
What is the purpose of the recommended practice for electrical installations in petroleum facilities?
What is the purpose of the recommended practice for electrical installations in petroleum facilities?
- To address energy conservation in petroleum facilities
- To review operation and maintenance of electrical systems
- To specify electrical equipment test standards
- To provide information on preventing accidental ignition of flammable liquids and gases (correct)
Why are the requirements for electrical systems in petroleum facilities more stringent?
Why are the requirements for electrical systems in petroleum facilities more stringent?
- To prioritize energy conservation
- To align with standard manufacturing facility requirements
- To reduce operation and maintenance costs
- Due to the specialized equipment and high rates of processing (correct)
What is excluded from the scope of the recommended practice for electrical installations in petroleum facilities?
What is excluded from the scope of the recommended practice for electrical installations in petroleum facilities?
- Specifications for engineering and construction contracts
- Energy conservation strategies
- Operation and maintenance guidelines
- Electrical equipment test standards (correct)
What is the focus of the recommended practice for electrical installations in petroleum facilities?
What is the focus of the recommended practice for electrical installations in petroleum facilities?
Which organization provides guidelines for area classification and selection of electrical equipment in petroleum facilities?
Which organization provides guidelines for area classification and selection of electrical equipment in petroleum facilities?
What is the primary purpose of positive-pressure ventilation in relation to classified locations?
What is the primary purpose of positive-pressure ventilation in relation to classified locations?
Which technique is primarily used for instrumentation and process control in classified areas?
Which technique is primarily used for instrumentation and process control in classified areas?
What can energy efficient electrical design lead to in terms of losses and costs?
What can energy efficient electrical design lead to in terms of losses and costs?
What is the potential range of electrical losses in the distribution and utilization equipment of a refinery power system?
What is the potential range of electrical losses in the distribution and utilization equipment of a refinery power system?
Which organization must approve electrical equipment for specific area classification?
Which organization must approve electrical equipment for specific area classification?
What are the alternative designs for installing equipment not suitable for classification?
What are the alternative designs for installing equipment not suitable for classification?
Which protection technique is NOT mentioned for electrical equipment in classified areas?
Which protection technique is NOT mentioned for electrical equipment in classified areas?
What is the primary purpose of intrinsically safe equipment and wiring methods?
What is the primary purpose of intrinsically safe equipment and wiring methods?
What is the focus of economic evaluation, power factor, and demand control in relation to electrical efficiency?
What is the focus of economic evaluation, power factor, and demand control in relation to electrical efficiency?
What can reduced losses in electrical equipment result in?
What can reduced losses in electrical equipment result in?
Which document provides guidelines for electrical equipment for specific area classification?
Which document provides guidelines for electrical equipment for specific area classification?
Which classification system is used for locations containing flammable gases or vapors?
Which classification system is used for locations containing flammable gases or vapors?
What are the classes into which flammable liquids are divided based on flash and boiling points?
What are the classes into which flammable liquids are divided based on flash and boiling points?
Which organization provides detailed guidelines for the classification of locations containing flammable liquids and gases?
Which organization provides detailed guidelines for the classification of locations containing flammable liquids and gases?
What are the criteria established by NFPA 70 for classifying locations?
What are the criteria established by NFPA 70 for classifying locations?
What determines the physical boundaries of a classified location?
What determines the physical boundaries of a classified location?
What serves as a reference for selecting and locating electrical equipment in classified locations?
What serves as a reference for selecting and locating electrical equipment in classified locations?
What are the categories used in the Zone system for classifying locations containing flammable gases or vapors?
What are the categories used in the Zone system for classifying locations containing flammable gases or vapors?
What is the purpose of a plot plan in the context of location classification?
What is the purpose of a plot plan in the context of location classification?
Which organization's classifications are applied to electrical installations in petroleum facilities by API RP 500 and 505?
Which organization's classifications are applied to electrical installations in petroleum facilities by API RP 500 and 505?
What are the categories used in the Division system for classifying locations containing flammable gases or vapors?
What are the categories used in the Division system for classifying locations containing flammable gases or vapors?
What is the term for locations not classified as Division 1, Division 2, Zone O, Zone 1, or Zone 2?
What is the term for locations not classified as Division 1, Division 2, Zone O, Zone 1, or Zone 2?
What is efficiency defined as?
What is efficiency defined as?
How much raw fuel is saved by a 1 kWh reduction in electrical usage?
How much raw fuel is saved by a 1 kWh reduction in electrical usage?
What can be used to calculate the dollar-per-kilowatt factor?
What can be used to calculate the dollar-per-kilowatt factor?
How much can cogeneration increase the generation cycle thermal efficiency by when waste heat is recovered?
How much can cogeneration increase the generation cycle thermal efficiency by when waste heat is recovered?
What is recommended for determining equipment efficiency if economic penalty factors are involved?
What is recommended for determining equipment efficiency if economic penalty factors are involved?
What should be clearly stated in the equipment specification if payment terms are contingent on receipt of test results?
What should be clearly stated in the equipment specification if payment terms are contingent on receipt of test results?
What should the economic evaluation account for, especially for very large projects?
What should the economic evaluation account for, especially for very large projects?
How can power costs be reduced?
How can power costs be reduced?
What should specifications for electrical equipment include consideration for?
What should specifications for electrical equipment include consideration for?
What does reduced losses in indoor applications do to the heat load on air conditioning equipment?
What does reduced losses in indoor applications do to the heat load on air conditioning equipment?
What does energy efficient electrical equipment normally demand?
What does energy efficient electrical equipment normally demand?
What is necessary to determine if the equipment costs will be offset by future energy savings?
What is necessary to determine if the equipment costs will be offset by future energy savings?
What is the typical efficiency of typical utility generating units?
What is the typical efficiency of typical utility generating units?
What is the temperature range for the exhaust gases used in the waste heat boiler?
What is the temperature range for the exhaust gases used in the waste heat boiler?
What are three examples of direct heating with turbine exhaust?
What are three examples of direct heating with turbine exhaust?
What is used to heat the product when gas turbines are used as generator drives to provide power for the transport pump motors?
What is used to heat the product when gas turbines are used as generator drives to provide power for the transport pump motors?
What is displaced by using the waste heat from the gas turbine’s exhaust in process plants?
What is displaced by using the waste heat from the gas turbine’s exhaust in process plants?
What is the purpose of the power recovery turbine?
What is the purpose of the power recovery turbine?
What is the typical output range of the generator used in the power recovery turbine system?
What is the typical output range of the generator used in the power recovery turbine system?
What type of generator is usually used for the power recovery turbine service?
What type of generator is usually used for the power recovery turbine service?
What is used as a source of electric power by dropping the line pressure to plant utility pressure through an expander?
What is used as a source of electric power by dropping the line pressure to plant utility pressure through an expander?
What is the efficiency of high-efficiency transformers that can be purchased?
What is the efficiency of high-efficiency transformers that can be purchased?
What are the two components of transformer losses?
What are the two components of transformer losses?
Which losses are considered to be constant for a given voltage?
Which losses are considered to be constant for a given voltage?
What are the most significant losses caused by the flow of load current in both primary and secondary windings of transformers?
What are the most significant losses caused by the flow of load current in both primary and secondary windings of transformers?
What is the major consumer of energy in process plants, typically accounting for 70% of the electrical energy consumption?
What is the major consumer of energy in process plants, typically accounting for 70% of the electrical energy consumption?
What are the motor losses consisting of, apart from core loss and stray-load loss?
What are the motor losses consisting of, apart from core loss and stray-load loss?
What is the purpose of suitable relaying in parallel operation of incoming utility lines?
What is the purpose of suitable relaying in parallel operation of incoming utility lines?
What should be considered when incoming circuits cannot be paralleled?
What should be considered when incoming circuits cannot be paralleled?
What should be included in a regular testing method for the automatic transfer scheme?
What should be included in a regular testing method for the automatic transfer scheme?
What should be considered for maintaining close voltage regulation when utility or plant voltage varies?
What should be considered for maintaining close voltage regulation when utility or plant voltage varies?
What can harmonic distortion cause in electrical systems?
What can harmonic distortion cause in electrical systems?
What must the electrical system be designed to accommodate in terms of short-circuit current?
What must the electrical system be designed to accommodate in terms of short-circuit current?
What is essential to minimize the number and duration of power outages?
What is essential to minimize the number and duration of power outages?
What should be calculated to ensure that plant and utility company requirements are met during motor starting?
What should be calculated to ensure that plant and utility company requirements are met during motor starting?
What is typically used to parallel incoming utility lines on the substation bus?
What is typically used to parallel incoming utility lines on the substation bus?
What should be reviewed for systems with appreciable nonsinusoidal harmonics?
What should be reviewed for systems with appreciable nonsinusoidal harmonics?
What should be known to determine the effect on motor starting and protective relay settings?
What should be known to determine the effect on motor starting and protective relay settings?
What is essential to consider for maintaining system protection and reliability?
What is essential to consider for maintaining system protection and reliability?
What type of auxiliaries are critical for air, fuel, and water supplies in power stations producing steam and electricity?
What type of auxiliaries are critical for air, fuel, and water supplies in power stations producing steam and electricity?
What type of construction can be used in isolated power stations where each generator has its own boiler or turbine, main bus, and auxiliary bus?
What type of construction can be used in isolated power stations where each generator has its own boiler or turbine, main bus, and auxiliary bus?
What serves to limit fault duty and isolate voltage dips during faults in a synchronizing bus scheme?
What serves to limit fault duty and isolate voltage dips during faults in a synchronizing bus scheme?
What is crucial for the reliable generation of reactive power by the generator field?
What is crucial for the reliable generation of reactive power by the generator field?
What are the two types of excitation systems commonly used for generators?
What are the two types of excitation systems commonly used for generators?
What should be examined to determine the frequency and nature of service disturbances, automatic reclosures, and outage lengths?
What should be examined to determine the frequency and nature of service disturbances, automatic reclosures, and outage lengths?
What should circuits be sized for in order to ensure continuous load carrying capacity?
What should circuits be sized for in order to ensure continuous load carrying capacity?
What should be provided by utilities to assess the reliability of the utility system?
What should be provided by utilities to assess the reliability of the utility system?
What should power contracts with utilities include consideration for?
What should power contracts with utilities include consideration for?
What should be examined to determine the capacity to carry the load continuously if any one circuit is out of service?
What should be examined to determine the capacity to carry the load continuously if any one circuit is out of service?
What should energy charges in power contracts with utilities include as part of the contract?
What should energy charges in power contracts with utilities include as part of the contract?
What should be examined to determine the reliability of the utility system?
What should be examined to determine the reliability of the utility system?
What is the formula for calculating power factor?
What is the formula for calculating power factor?
What is the unit of expression for apparent power consumed by an electrical system?
What is the unit of expression for apparent power consumed by an electrical system?
What is the primary purpose of power factor correction capacitors in a system?
What is the primary purpose of power factor correction capacitors in a system?
What is the equivalence of British thermal units (Btu) to other units?
What is the equivalence of British thermal units (Btu) to other units?
What determines the energy loss in power cables?
What determines the energy loss in power cables?
What is the relationship between kilowatts (kW) and kilovolt-amperes reactive (kvar) in an electrical system?
What is the relationship between kilowatts (kW) and kilovolt-amperes reactive (kvar) in an electrical system?
What action can be taken to reduce higher-than-necessary currents on the distribution system due to low power factor?
What action can be taken to reduce higher-than-necessary currents on the distribution system due to low power factor?
What is the primary benefit of installing capacitors at the motor terminals and switching them on and off with the motor?
What is the primary benefit of installing capacitors at the motor terminals and switching them on and off with the motor?
What is the relationship between raw fuel consumption and electricity production in a conventional utility generating station?
What is the relationship between raw fuel consumption and electricity production in a conventional utility generating station?
What is the measure of the percentage of kVA that is doing useful work in an electrical system?
What is the measure of the percentage of kVA that is doing useful work in an electrical system?
What is the primary effect of low power factor in a system?
What is the primary effect of low power factor in a system?
What is the primary factor that determines the energy loss in power cables?
What is the primary factor that determines the energy loss in power cables?
What is a factor to be considered for the design of protective relaying and system control schemes?
What is a factor to be considered for the design of protective relaying and system control schemes?
What should be taken into consideration for the characteristics of a facility substation?
What should be taken into consideration for the characteristics of a facility substation?
What may be required when the utility system is not stiff enough to allow full-voltage starting of the largest motor?
What may be required when the utility system is not stiff enough to allow full-voltage starting of the largest motor?
What is a consideration for maintaining close voltage regulation when utility or plant voltage varies?
What is a consideration for maintaining close voltage regulation when utility or plant voltage varies?
What impacts all factors and is crucial in power system design?
What impacts all factors and is crucial in power system design?
What is the purpose of dual-purpose fault clearing devices?
What is the purpose of dual-purpose fault clearing devices?
Which system is the easiest to understand, operate, and troubleshoot but provides no alternate power source?
Which system is the easiest to understand, operate, and troubleshoot but provides no alternate power source?
What is the primary function of single-purpose fault clearing devices?
What is the primary function of single-purpose fault clearing devices?
Which system offers uninterrupted service continuity and voltage regulation to all loads, but is complex and costly?
Which system offers uninterrupted service continuity and voltage regulation to all loads, but is complex and costly?
What is the purpose of establishing a zone of protection around each system element?
What is the purpose of establishing a zone of protection around each system element?
What do power system planning, design, and operation require continual and comprehensive analyses to evaluate?
What do power system planning, design, and operation require continual and comprehensive analyses to evaluate?
What is the importance of obtaining optimum settings for fault clearing device coordination?
What is the importance of obtaining optimum settings for fault clearing device coordination?
What must fault-current interruption devices have to handle available fault currents and prevent equipment failure?
What must fault-current interruption devices have to handle available fault currents and prevent equipment failure?
What is the primary function of a relay in the electrical system?
What is the primary function of a relay in the electrical system?
What can faults not promptly isolated from the power source cause?
What can faults not promptly isolated from the power source cause?
What is the purpose of proper selection and application of relays?
What is the purpose of proper selection and application of relays?
What is crucial in system design and impacts all factors?
What is crucial in system design and impacts all factors?
What can relays be adjusted for?
What can relays be adjusted for?
Which system offers better service continuity and flexibility than a simple radial system, but with higher initial investment?
Which system offers better service continuity and flexibility than a simple radial system, but with higher initial investment?
What is required for relays to ensure proper settings and operation?
What is required for relays to ensure proper settings and operation?
What do system studies include to evaluate current system performance and the effectiveness of alternative plans for expansion?
What do system studies include to evaluate current system performance and the effectiveness of alternative plans for expansion?
What initiates the operation of a breaker in the electrical system?
What initiates the operation of a breaker in the electrical system?
What is the most correct about a simple radial system?
What is the most correct about a simple radial system?
What is the focus of IEEE Std 242 and WEE Std 141?
What is the focus of IEEE Std 242 and WEE Std 141?
What is required to handle available fault currents and prevent equipment failure?
What is required to handle available fault currents and prevent equipment failure?
What is the primary function of fault sensing devices in the electrical system?
What is the primary function of fault sensing devices in the electrical system?
What is the primary purpose of fault considerations in system design?
What is the primary purpose of fault considerations in system design?
What must fault clearing devices have to ensure proper operation during faults?
What must fault clearing devices have to ensure proper operation during faults?
What is the primary purpose of power factor correction capacitors in a system?
What is the primary purpose of power factor correction capacitors in a system?
What serves to limit fault duty and isolate voltage dips during faults in a synchronizing bus scheme?
What serves to limit fault duty and isolate voltage dips during faults in a synchronizing bus scheme?
What are the categories used in the Zone system for classifying locations containing flammable gases or vapors?
What are the categories used in the Zone system for classifying locations containing flammable gases or vapors?
What is the purpose of the power recovery turbine?
What is the purpose of the power recovery turbine?
What is essential to consider for maintaining system protection and reliability?
What is essential to consider for maintaining system protection and reliability?
What are the two components of transformer losses?
What are the two components of transformer losses?
What is the unit of expression for apparent power consumed by an electrical system?
What is the unit of expression for apparent power consumed by an electrical system?
What is the relationship between raw fuel consumption and electricity production in a conventional utility generating station?
What is the relationship between raw fuel consumption and electricity production in a conventional utility generating station?
What is the purpose of the recommended practice for electrical installations in petroleum facilities?
What is the purpose of the recommended practice for electrical installations in petroleum facilities?
What should specifications for electrical equipment include consideration for?
What should specifications for electrical equipment include consideration for?
What is necessary to determine if the equipment costs will be offset by future energy savings?
What is necessary to determine if the equipment costs will be offset by future energy savings?
What is the purpose of a plot plan in the context of location classification?
What is the purpose of a plot plan in the context of location classification?
What should be considered when applying fuses to facility power systems?
What should be considered when applying fuses to facility power systems?
What is a characteristic of fuses designed for special applications such as motor starter circuits?
What is a characteristic of fuses designed for special applications such as motor starter circuits?
What must be considered when coordinating fuses for the power system?
What must be considered when coordinating fuses for the power system?
Where are circuit breakers not listed for direct use according to NRTL?
Where are circuit breakers not listed for direct use according to NRTL?
What is a characteristic of circuit breakers used on systems with nominal system voltages of 600 V-15,000 V?
What is a characteristic of circuit breakers used on systems with nominal system voltages of 600 V-15,000 V?
What is the interrupting medium generally used for circuit breakers on systems with nominal system voltages of 15,000 V-35,000 V?
What is the interrupting medium generally used for circuit breakers on systems with nominal system voltages of 15,000 V-35,000 V?
Where are circuit breakers installed when the utility system is not stiff enough to allow full-voltage starting of the largest motor?
Where are circuit breakers installed when the utility system is not stiff enough to allow full-voltage starting of the largest motor?
What is the primary purpose of a regular preventive maintenance program for circuit breakers?
What is the primary purpose of a regular preventive maintenance program for circuit breakers?
What is the primary purpose of switchgear applications?
What is the primary purpose of switchgear applications?
What is the interrupting medium generally used for higher voltage systems in individual free-standing outdoor types of circuit breakers?
What is the interrupting medium generally used for higher voltage systems in individual free-standing outdoor types of circuit breakers?
What is essential for circuit breakers used on systems with nominal system voltages less than or equal to 600 V?
What is essential for circuit breakers used on systems with nominal system voltages less than or equal to 600 V?
What is the primary purpose of using relays for sensing fault conditions in circuit breakers?
What is the primary purpose of using relays for sensing fault conditions in circuit breakers?
Study Notes
Electrical Efficiency and Economic Evaluation of Energy Efficient Equipment
- Reduced losses in indoor applications decrease the heat load on air conditioning equipment.
- A 1 kWh reduction in electrical usage saves the equivalent of 4 to 5 kWh of raw fuel due to losses in electricity generation, transmission, and distribution.
- Efficiency is defined as the ratio of power output to power input or energy output to energy input.
- Specifications for electrical equipment should include consideration for energy efficiency, including operating points and efficiency curves.
- Economic evaluation is necessary to determine if the equipment costs will be offset by future energy savings.
- Energy efficient electrical equipment normally demands a premium price, and a dollar-per-kilowatt factor can determine the value of saved energy for specific projects.
- The dollar-per-kilowatt factor can be calculated using simple payback, taking into account factors such as income tax rate, effective interest rate, and power cost escalation rate.
- Power costs can be reduced by investing in in-plant generation, particularly through cogeneration, which uses waste heat for process heating or power generation.
- Cogeneration can increase the generation cycle thermal efficiency from about 25% to about 70% when waste heat is recovered.
- Witnessed testing is recommended for determining equipment efficiency if economic penalty factors are involved.
- Payment terms contingent on receipt of test results should be clearly stated in the equipment specification.
- The economic evaluation should account for factors such as depreciation, tax investment credits, and variable escalation rates, especially for very large projects.
Design Considerations for Petroleum Facility Power Systems
- The text discusses the importance of evaluating design considerations for developing reliable and cost-effective power systems for continuously run petroleum facilities.
- It covers all aspects of facility power systems, including incoming lines for purchased power, in-plant generation, substations, transformers, switchgear, overhead distribution systems, voltage levels, system arrangements, protective relaying, fault currents, and system stability.
- Facility power stations not connected to public utility systems must be designed with redundancy to ensure self-sufficiency for various operating contingencies.
- Power cables' energy loss depends on the resistance of the cable and the amount of current expected to flow in the circuit.
- Apparent power consumed by an electrical system is expressed in kilovolt-amperes (kVA) and consists of a kilowatt (kW) component and a kilovolt-ampere reactive (kvar) component.
- Power factor is the ratio of kW to kVA and provides a measure of the percentage of kVA that is doing useful work.
- Low power factor in a system can result in higher-than-necessary currents on the distribution system, leading to higher losses.
- Actions to increase power factor and reduce associated losses include using high power factor rated equipment, operating high efficiency induction motors at close to design horsepower, and using power factor correction capacitors to supply the reactive requirements of inductive loads.
- When capacitors are applied to induction motors, the greatest benefit is obtained if the capacitors are installed at the motor terminals and switched on and off with the motor.
- The text provides definitions and conversion factors useful in energy discussions, such as the equivalence of British thermal units (Btu) to other units, the definition of a quad, and the conversion of horsepower to kilowatts.
- Due to thermal losses, approximately 10,000 Btu of raw fuel are consumed to produce 1 kWh of electricity in a conventional utility generating station.
- The text emphasizes the need for equipment evaluation at critical speeds and evaluating the effects of system harmonics generated by adjustable frequency drive equipment.
Electrical Fault Clearing Devices and Relaying Considerations
- Fault sensing device detects fault in electrical system
- Signal sent to fault clearing devices to isolate faulted segment
- Fault clearing devices must have adequate interrupting and momentary withstand ratings
- Dual-purpose devices provide sensing and interrupting functions in same enclosure (e.g., fuses, circuit breakers)
- Single-purpose devices receive electrical signal from relay to operate mechanical contacts to interrupt electric current
- Zone of protection established around each system element (e.g., bus, transmission line)
- Coordinated fault clearing devices must properly isolate faulted section
- Coordination margins outlined in standards such as WEE Std 141 and IEEE Std 242
- Importance of obtaining optimum settings for fault clearing device coordination
- Relay detects abnormal system conditions and initiates breaker operation
- Proper selection and application of relays important for protection of feeders, transformers, and rotating machines
- Relays can be adjusted for selectivity and proper operation ranges, and require testing and inspection for proper settings and operation
Electrical Distribution and Utilization System Design Considerations
- Electrical distribution and utilization system must be designed for regular inspection and maintenance to ensure reliable operation.
- Maintenance of electrical facilities for a petroleum facility is often done at the same intervals as other process equipment.
- Avoid connecting unrelated process equipment that cannot be shut down during the primary facility shutdown.
- Design of electrical systems should consider potential facility additions or modifications, including equipment fault duty ratings and provisions for future expansion.
- When a utility supplies part of the facility power and operates in parallel with plant generated power, considerations include division and interchange of real and reactive power, protective relaying, and service restoration procedures.
- Power interchanges between utility and industrial systems can vary due to excess plant power generation, utility power restrictions, or load adjustments to maintain constant demand on the utility system.
- Contracts for the purchase of utility power should include the amount of kilowatts and kilovars and their division or interchange between the utility and the facility.
- Protective relaying must be provided to protect the plant and its generation from faults or power loss in the utility system.
- Service restoration procedures are necessary in various fault or switching conditions that may cause facility and utility generating systems to separate.
- The selection of system voltages in a facility is primarily based on economics, with consideration given to factors such as total connected load, planning for future growth, and plant standardization of equipment.
- The voltage levels in a facility are categorized as low (≤600 V), medium (601 V to 69,000 V), and high (>69,000 V), each serving different purposes.
- Four basic types of power system arrangements are available: radial, primary-selective radial, secondary-selective radial, and secondary-selective parallel.
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